If you can't get the stains out you might see if you can buy or make
new covers. We have a couple of wicker chairs with separate cushions
on them. One our dog has chosed as her bed. He body oils soiled
it. I tried everything washing, spraying, etc. But, could not get
the stains out. I had some old flowered pillow cases (the sheet had
worn out). I took two cases sewed them together and then put the
cushion inside. I just tuck the extra in under the end. The pillow
cases wash up nicely when they get dirty.

One one old sofa I had a sofa cover once. This was years ago, when

our son was little and our sofa was old.